Abstract
This paper presents the development of an analysis technique and software program to quantify the anisotropy of pyrolytic carbon or ultra-fine grain graphite using selected area electron diffraction (SAED) patterns from a transmission electron microscope. Results serve as input to a computer program that calculates the Bacon anisotropy factor (BAF) and orientation parameter (R). This was achieved by analyzing the SAED patterns to determine the full width half maximum of the two peaks on the (0 0 0 1) diffraction ring, converting the SAED data into the same format as the X-ray data and then calculating the BAF and R. The methodology of calculating the BAF and R values from the SAED patterns was confirmed by comparing the calculated values with the BAF values resulting from ellipsometry measurements on two identical isotropic pyrolytic carbon (PyC) samples and resulted in a difference of less than 0.26%, while measurements on an anisotropic turbostratic pyrolytic carbon showed almost a 40% difference which may be due to the larger planar spacing changing the extraordinary refractive index and extraordinary extinction coefficient.
| Original language | English |
|---|---|
| Pages (from-to) | 410-420 |
| Number of pages | 11 |
| Journal | Carbon |
| Volume | 60 |
| DOIs | |
| State | Published - Aug 2013 |
Funding
The authors would like to acknowledge the assistance provided by the research staff at Oak Ridge National Laboratory, Dr. J. Hunn, Dr. J. Miller, B. Jolly, and E. Fray for assistance with the PyC deposition, Dr. G.E. Jellison, Jr., and Dr. J. Hunn for in-depth discussions about, and assistance with, the ellipsometry measurements, and Dr. C. Parish at the ShaRE User Facility for assistance with FIB and TEM work. Financial support for this research was provided by the United States Department of Energy under NERI contract #FC07-06ID14732 , and Idaho National Laboratory under contract #DE-AC07-05ID14517 . Research supported by ORNL’s Shared Research Equipment (ShaRE) User Program , which is sponsored by the Office of Basic Energy Sciences , the U.S. Department of Energy . Use of the EMAL JEOL 3011 is supported by NSF Grant #DMR-0315633 , and the EMAL FEI Helios is supported by the University of Michigan College of Engineering .